The present invention relates generally to thermally energized compressors and pumps for fluids, and more particularly to such devices employing pumping cells wherein the pumped fluid is alternately heated and cooled by a heated transfer medium.
In thermodynamic systems it is generally necessary to provide positive circulation of working fluid to pass the fluid through the system components which effect a thermodynamic working cycle. Where mechanical energy for this purpose is available from an outside source or is generated by the thermodynamic cycle and a portion diverted to the operation on mechanical pressure generators, the problem of fluid circulation is resolved. Examples of such arrangements are feedwater pumps of conventional Rankine-cycle steam engines driven off the shaft of the engine or turbine.
Provision for circulation of working fluid is more difficult where the thermodynamic cycle is to be operated without utilizing external energy or energy of the thermodynamic system to operate pressure generators. Instances wherein the working fluid changes phase from liquid to vapor, vapor pumps may be utilized to elevate the fluid to a header tank to provide static pressure, but where the working fluid is a gas, or where the working fluid is a liquid to be retained in the liquid state, mechanical devices or pressure generators are necessary in prior art systems.
A major problem is presented in many applications, such as those involving a corrosive fluid, systems wherein working pressure is substantially above or below atmospheric, or where leakage associated with seals utilized in mechanical pressure generators, cannot be tolerated. Thus, circulation of working fluid in sealed thermodynamic systems without utilizing mechanical pressure generators would make possible systems otherwise unfeasible in such fields as nuclear engineering or solar-powered thermal devices.
It is therefore an object of the present invention to provide compressor and pump means for fluid media operated by alternate heating and cooling of the media in a chamber of fixed volume, flow of the medium being governed by one-way valves operated by pressure changes in the chamber which are caused by the heating and cooling.
An object of the invention is revision for pumping of liquid media communicating with such chambers, and utilizing compressable gaseous fluid.
It is an object of the invention to provide firmly operated pumping cells for circulating working fluid in conventional thermodynamic cycles.